Carth Onasi called her back to Telos in order to find out more about Revan.

Atris acts as if she didn't have anything to do with the return of the Exile. SHE was the one who publicized the return of the Exile into known space in order to draw out the Sith. But when we tell her that we encountered the Sith she acts as if she doesn't know anything because if she would have admitted it, the destruction of Peragus would be HER FAULT.

I wouldn't say that Peragus could be considered her fault, mostly because I doubt that she would've been counting on the Exile even going to Peragus. Truthfully, while it is true that the Exile can be responsible for it, the problem with that station is that it lacks personnel, and while it could certainly be restaffed, that would take some time. Even in the instance that the Exile chooses not to destroy it, it obviously still happens, but it can't really be pinned in the Exile. Either way, it is interesting that most blame the exist for it, purely because of circumstantial evidence. And it is because of this that most in the galaxy think the Exile had something to do with it. Especially G0-T0, who, while he might've heard something from the HK-50 aboard the Harbinger(though it would've only been from before it left the ship), still goes on the accepted view that the Exile is to blame. What about any other ship that would've come from that direction, before the Exile arrived? Maybe some were, but none that are mentioned in-game.